A laser beam profiler (alto termed simply a “laser profiler”) captures and determines the spatial intensity profile of a laser beam at a particular plane transverse to the beam propagation path. The camera resides above the plane and the camera lens axis resides at an acute angle relative to the plane. Laser profilers are useful in a wide range of inspection and manufacturing operations where the user desires to measure and characterize surface details of a planar object via triangulation. One example is the inspection of keyboards in which the profiling task determines whether all keys are at a similar height. One form of laser profiler uses a vision system camera having an image sensor (or “imager”) that can be based upon a CCD or CMOS design. The imager defines a predetermined field of grayscale or color-sensing pixels on an image plane that receive focused light from an imaged scene through a lens. The profiler uses a particular lens assembly that directs reflected laser light from the planar scene to the sensor at an acute angle with respect to the camera sensor's optical axis (which is perpendicular to the image plane). In this manner, the non-perpendicular angle between the laser axis, lens axis and sensor's image plane can fulfill the so-called Scheimplfug principle so as to define a sharp image of the laser line at every measurement distance (described further below). That is, normally when a camera axis is directed at a non-perpendicular angle to a planar scene, only a small crossing width of the overall height of the acquired image is in sharp focus and the focus fades above and below this region.
A significant challenge to performing accurate laser profiling is that the relative angles of the laser axis with respect to the lens axis should be highly accurate. Likewise the distance between the spaced-apart laser and the lens should be known to a high degree of accuracy. Setting up a an arrangement of mounting fixtures for the camera and laser, and then calibrating this arrangement is time consuming and can lead to variability in the system's overall accuracy and performance.
It is therefore desirable to provide a laser profiling system for use with a vision system camera that allows for accurate and repeatable setup of a laser profiling arrangement with reduced time and effort.